THIS GUIDE IS UNFINISHED, AND MAY NEVER BE FINISHED.
This is not a step-by-step instruction manual but rather a collection of resources and things to consider when tuning Linux systems for low-latency, low-jitter gaming.
This guide is targeted toward more experienced users, due to the fact that many settings listed here cannot be blindly applied, and require some understanding of what is going on. That said, I don't claim to be an authority on this subject either, and some information here may be incorrect or misleading.
Before reading this guide, please go through PC-Tuning to learn how to properly configure your hardware and UEFI/BIOS settings (you can ignore the Windows-specific steps).
- 1. Distributions
- 2. Kernel Parameters
- 3. Schedulers
- 4. Display servers, compositors, & window managers
- 5. libinput
- 6. NVIDIA GPUs
- 7. AMD GPUs
- 8. Intel GPUs
- 9. Audio
- 10. File systems & storage
- 11. Networking
- 12. Wine
- 13. Miscellaneous
- 14. Further Reading
Arch-based distribution that comes with its own optimized repositories and offers custom kernels with various patches (& optimizations such as LTO). Highly recommended.
I'm not going to go too deep into kernel-related tuning (besides kernel parameters) in this guide because the CachyOS kernels are essentially as good as it gets.
Information about the CachyOS kernels
Information about the CachyOS repositories
Source-based distribution which may offer minor performance gains over CachyOS (in exchange for time spent configuring & compiling). Gentoo also now provides pre-built binaries for common packages (including some built specifically for the x86-64-v3 ISA, similar to CachyOS), but it's still more work than CachyOS for relatively little benefit.
Don't use kernel parameters if you don't know what effects they have! This applies doubly so for random kernel parameters you find online with no explanation of what they do.
Some of the parameters listed may compromise the security or stability of your machine.
If you want to disable power saving related settings, I would advise disabling them in both UEFI/BIOS settings as well as kernel parameters. I say this due to stuttering that I experienced in the past, which was caused by having processor C-States disabled in UEFI but not in kernel parameters. I assume that something tried to "override" my UEFI settings.
And similarly to the issue I personally experienced, the impression I get is that you should be redudant with your settings, just to be on the safe side. Even Intel recommends using all 3 of the following parameters: intel_idle.max_cstate=0, processor.max_cstate=0, and idle=poll, despite the fact that idle=poll should in theory make the other two redundant. This may just be paranoia though.
| Parameter | Explanation |
|---|---|
mitigations=off |
Disable CPU security mitigations, which often come with a performance penalty. This will make your system significantly less secure, apply at your own risk. |
nowatchdog |
Disable watchdog timers to reduce interrupts. |
nosoftlockup |
Don't log backtraces for processes that execute for longer than 120 seconds without yielding. Probably doesn't matter for any games. |
audit=0 |
Disable the audit framework to marginally reduce overhead (mentioned in section 8 of RHEL's latency tuning guide). |
usbcore.autosuspend=60 |
Set USB autosuspend timer to 60 seconds (default: 2). Alternatively, replace 60 with any other value. A negative value will disable autosuspend entirely. |
workqueue.power_efficient=false |
Disable power-efficient workqueues if enabled in your kernel configuration, since it may cause cache misses due to workqueues being scheduled onto different cores. |
skew_tick=1 |
Skew timer ticks on different cores to reduce lock contention. |
threadirqs |
Thread interrupt handlers by default. |
tsc=reliable |
Disable clocksource verification for TSC, which may slightly reduce overhead. Not recommended due to the potential for clock desync. |
preempt=full |
Allow preemption of almost all kernel code. |
nohz_full=all |
Use tickless mode on all cores wherever possible (specifically, when there is at most one runnable task on a core). Alternatively, you can replace all with a range or comma-separated list of cores to make tickless, e.g. 2-5,7,8. This is not necessarily beneficial. In addition, isolcpus can be used to force a specific task to always run tickless. |
cpufreq.default_governor=performance |
Set the default frequency scaling governor to performance. |
pcie_aspm=off |
Force ASPM off for all PCIE devices. Make sure to disable ASPM in UEFI/BIOS settings as well. |
processor.max_cstate=0 |
Don't allow processor to sleep deeper than the C1 state. This will prevent your CPU from reaching its maximum single-core boost clock (if running stock frequencies), but reduces jitter substantially. This will increase idle power usage. Make sure to disable C-States in UEFI/BIOS settings as well. |
idle=poll |
Force CPU into the C0 state (significantly increasing idle power usage). Don't use if you have hyperthreading/SMT enabled. Also, Linux kernel documentation says that this parameter provides no performance advantage on CPUs with MWAIT support, which is all modern x86 CPUs. However, the aforementioned Intel latency tuning guide (which was updated in 2017) still recommends this parameter, so I'm not sure what to make of this one. RHEL's latency tuning guide also recommends using this parameter. |
Use i7z to verify that your processor is running at the correct frequency & C-States.
| Parameter | Explanation |
|---|---|
intel_pstate=disable |
Disable the intel_pstate driver. |
intel_idle.max_cstate=0 |
Disable the intel_idle driver and fall back on acpi_idle. |
modprobe.blacklist=iTCO_wdt |
nowatchdog may fail to disable the Intel TCO watchdog, this is a fix (not necessary on CachyOS). |
TODO
If unsure, BORE and rusty are both solid picks (BORE is used by default in CachyOS). But the best option will depend on your choice of game, your hardware, and whether you have anything else running while playing (e.g. recording software, Discord). Some schedulers may improve in performance in the future due to updates.
If experiencing strange freezing or other performance issues, changing schedulers may be a good idea.
Obviously, a less bloated system is going to run better than a bloated system, so you'll probably want to avoid any DE/WM that runs an excessive number of operations in the background. But even "light" WMs can still have performance bugs, and the size on disk/RAM usage of a WM does not necessarily tell you how it actually performs.
The most popular implementation of the X11 display protocol. The more mature and better-supported option compared to Wayland. Xorg may also make it easier to configure GPU and input related settings, depending on your setup and needs.
Ensure you disable desktop composition while gaming if using Xorg. The way to do this will depend on your choice of compositor/DE. I personally don't use desktop composition anywhere, because the latency bothers me more than the tearing even on the desktop, but it's up to you.
Not a display server in itself, but a protocol implemented by various display servers (called "Wayland compositors"). Should offer a smoother experience than Xorg on NVIDIA due to explicit sync & a few Xorg-specific driver bugs (unless your compositor is super bloated). Also offers the potential for tear-free gaming with relatively low latency, without the need for VRR.
If you want the lowest possible latency, you'll need to make sure that the compositor you choose has the capability to enable tearing in games (i.e. to disable Vsync), and has support for explicit sync (if on NVIDIA). Again though, just having these capabilities does not automatically make a compositor low-latency.
The only compositor I know of that lets you force tearing outside of fullscreen applications is labwc, if that's something you care about. It currently does not support explicit sync, however, and somewhat comparable latency outside of fullscreen (within 2ms) can be achieved on sway with max_render_time and Hyprland with render_ahead_of_time (both of these compositors have explicit sync support). However, Hyprland's implementation has inherent inconsistency due to being based around the expected time to render a frame (averaged over a period of one second), so keep that in mind.
You may want to use a greeter such as ReGreet that runs in Wayland rather than Xorg (I noticed SDDM leaves Xorg running in the background, not sure about others).
Of potential interest:
wlrootsenvironment variables (especiallyWLR_RENDERER)
To convert mouse sensitivity from a percentage (e.g. 25%) into a libinput Accel Speed value (e.g. -0.75), simply subtract 1 from the percentage (e.g. 0.25 - 1 = -0.75). Make sure you set your Accel Profile to flat as well (to disable acceleration).
If you want to separate vertical and horizontal sensitivity (Xorg only), what you have to do is create a file in /etc/X11/xorg.conf.d/ called something like 50-mouse-sensitivity.conf, with the following content:
Section "InputClass"
Identifier "All Mice"
MatchIsPointer "on"
Driver "libinput"
Option "AccelProfile" "flat"
Option "TransformationMatrix" "1 0 0 0 1 0 0 0 1"
EndSection
TransformationMatrix is a matrix of values that can be used to warp mouse input in various ways. But all you need to know for this section is that your mouse's horizontal speed can be controlled with the first value of this matrix, and your mouse's vertical speed can be controlled with the fifth value of this matrix.
For instance, you can set your mouse to 25% horizontal sensitivity and 50% vertical sensitivity with Option "TransformationMatrix" "0.25 0 0 0 0.5 0 0 0 1".
Instead of MatchIsPointer, you can do something like MatchVendor "Razer" or MatchProduct "Viper 8K" if you don't want the configuration to apply to all mice: in this example, it will search for the substring "Viper 8K" within the product's name, so you don't need to know the full, exact name of the mouse that your system sees.
libinput adds eager debouncing to all mice by default. This does not add latency to clicks or releases in most cases, but it prevents you from making very short or very fast clicks, and is completely unnecessary on mice that use optical switches or latch debouncing, as well as mice that already offer configurable debounce time in their software.
To disable it, create the file /etc/libinput/local-overrides.quirks (if it does not exist already), and add the following lines to it:
[Mouse Debouncing]
MatchUdevType=mouse
ModelBouncingKeys=1
You can also use evdev as a driver instead of libinput on Xorg, which may potentially provide lower latency (haven't tested). For this, you'll need to install a package like xf86-input-evdev or similar (not libevdev).
Your configuration file will look something like this:
Section "InputClass"
Identifier "Mouse"
MatchIsPointer "on"
Driver "evdev"
Option "AccelerationScheme" "none"
Option "AccelerationProfile" "-1"
Option "VelocityReset" "30000"
EndSection
This is just a basic configuration file to set all pointers to use evdev, to disable mouse acceleration, and to set VelocityReset to 30 seconds (meaning that the mouse's subpixel position will only be discarded after 30 seconds of inactivity, rather than the default of 300ms).
Like with libinput, you can use the TransformationMatrix option to set a sensitivity value. However, you can also use the ConstantDeceleration option instead, as described here. This requires deleting the AccelerationScheme line.
You may additionally want to force all keyboards to use evdev with MatchIsKeyboard.
This section is written with Xorg & the proprietary NVIDIA drivers in mind, but much of this applies on Wayland too.
-
OpenGL environment variables: Of particular interest is the section on
__GL_YIELD. It's also worth looking into__GL_MaxFramesAllowed, but I can't find any official documentation for it. -
Kernel Module Parameters: Notable are
NVreg_InitializeSystemMemoryAllocationsandNVreg_UsePageAttributeTable, though CachyOS already sets these on its own. -
Tips and tricks: Of particular interest are the sections on overclocking, setting static clocks, configuring fan speed on login, and the
nvidia_drm.modesetkernel parameter (which CachyOS also sets on its own). -
Custom EDID: CRU works fine through Wine as long as you export the EDID and load it this way.
-
Lower voltage: Scuffed, but should work on all cards.
-
Raise voltage: Not sure if this works on newer cards.
The settings you configure with nvidia-settings sometimes aren't automatically loaded by the system on startup. Make sure to run nvidia-settings --load-config-only at some point after starting your display server.
Ensure Sync to VBlank, Force Composition Pipeline, and Force Full Composition Pipeline are disabled.
Disable Dithering within the Controls section for your display.
TODO
TODO
TODO
TODO
TODO
Enable Wine's native Wayland driver if on Wayland.
If running Direct3D games with Wine through the command line or a script, ensure you're using dxvk. Also, consider using the environment variable WINEDEBUG=-all to marginally reduce overhead.
If on an AMD or Intel GPU, consider static-wine32 to take advantage of LTO for 32-bit Windows games.
wine-osu provides low-latency audio and various other patches that may potentially improve performance.
-
gpu-screen-recorderis by far the best recording/clipping/streaming tool for Linux if you don't need too many features. If you need the functionality offered by OBS instead, consider usingobs-vkcapture, and potentiallyobs-vaapiif on an Intel or AMD GPU. -
Don't use
irqbalance. Manually setting IRQ affinities is also typically not necessary on Linux either; the kernel does a good job on its own. -
Use
evhzorMouseTester(through Wine) to ensure that your mouse is polling at the correct rate. ForMouseTester, you may have to hover your cursor over the data plot window to get accurate results. -
Add custom rules for your games if using
ananicy-cpp(enabled by default in CachyOS). Make sure to useananicy-cpprather thanananicy. Also, don't useananicy-cppin combination withgamemode. -
Choose a good cursor theme, I like Windows Classic Dark.
How do I build a real-time audio workstation on Linux?
Low Latency Performance Tuning for Red Hat Enterprise Linux 7